Feature Request: File upload progress indicator

**Is your feature request related to a problem? Please describe.**
When uploading large batches of prompts, the call to [`Client.files.upload`](https://github.com/googleapis/python-genai/blob/dd3df9b19e7cce249773794139f86d0c87ca64f7/google/genai/files.py#L583-L589) blocks with no indication of progress, for a long time.

**Describe the solution you'd like**
I would like a clear visual indicator, such as a progress bar, that progress is being made

**Describe alternatives you've considered**
N/A

**Additional context**
When uploading very large files via [`client.files.upload`](https://github.com/googleapis/python-genai/blob/dd3df9b19e7cce249773794139f86d0c87ca64f7/google/genai/files.py#L583-L589) , I would really like to see visual feedback.